In order to replace burst sections of such water supply pipelines, a trench or hole is dug down to and along the burst section of the pipeline. The burst section is then cut out from the pipeline and replaced with a new pipe section which is to be coupled at both ends to the ends of the existing pipeline by couplings.
Known, but not necessarily commonly known, couplings have a barrel section bridging and surroundings the ends of the old and new pipeline sections, with the barrel receiving at both ends elastomeric sealing rings to form a seal between the inside of the barrel and the circumferences of the existing and new pipe sections. The sealing rings are of an axially tapered configuration and are forced into matingly internally tapered ends of the barrel by annular cylindrical coupling members surrounding the respective pipe sections and axially connected by bolts extending through lugs in the coupling members at each end of the coupling and along the length of the barrel. The bolts when tightened progressively force the sealing rings into the opposite ends of the barrel whilst compressing the sealing rings to expand them radially outwardly into tight sealing engagement within the ends of the barrel and radially inwardly into tight sealing engagement around the circumferences of the pipe sections being joined. A similar coupling is used to couple the opposite end of the new pipe section to the adjacent end of the existing pipe section. Multiple axially extending bolts are utilised equally spaced around the coupling to provide an even distribution of force on the sealing rings. There may be up to sixteen, or even more, axially extending bolts.
However, because of the location of the connecting bolts with such known couplings, access to beneath the pipe sections is required when tightening the bolts, thus producing back strain, whilst, because of the number of bolts to be tightened, the task of installing the coupling can be time consuming.
It is therefore an object of the present invention to provide a coupling which overcomes, or at least minimises, the above disadvantages with known couplings, whilst also accommodating different diameters of pipe sections to be coupled and also differences between the diameters of the existing pipe and the diameter of the new pipe section. For example the existing pipe may be a metal pipe and the new replacement pipe section may be PVC having a thinner wall thickness, but providing an internal diameter the same as that of the existing pipe but with a smaller external diameter.